What is the right spark plug and gap for my small engine?

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Checking and changing spark plugs is an essential step in routine small engine maintenance and when troubleshooting problems with your lawn mower, snow blower or other outdoor power equipment.

Before doing any small engine repair or maintenance, be sure to check your manual for recommendations on specific parts numbers and safety precautions.

Spark Plug Type & Gap Chart for Briggs & Stratton Engines

Now that you’ve found the part you’d like to replace, you can use the chart below to identify the genuine Briggs & Stratton replacement spark plug and gap recommendation.

 Be sure to use the right spark plug! Although several different spark plugs may screw into the engine, using the incorrect one will result in performance problems and possible internal engine damage.

Spark Plug Gap Small Engine Briggs & Stratton

Flathead Engine Spark Plugs & Gaps

Also known as L head or Side Valve Engines, these engines are commonly used for walk behind lawn mowers and pressure washers.

Replacement Part Type Replacement Spark Plug Options by
Briggs & Stratton Part Number
Spark Plug Gap
Standard Resistor 796112S
Electromagnetic Suppression (EMS) 697451 .030”
Extended Life Series® L-Head Spark
Plug Platinum
5062 (5062D, 5062H)
Champion CJ8, RCJ8, RJ19HX, J19LM, and RJ19LM 796560
5062 (5062D, 5062H)
Champion RJ19LMC used in
Quantum engines
591868 .020” Engines built after Code Date 110630x
.030” – built before Code Date 110701xx*
Champion RJ2YLE used in Quantum Series 625, 675, & 725 engines built after Date Code 110701xx


*Not for Quantum engines built before Date Code 110701xx or other L Head engines

"Surefire" RJ2YXLE in Craftsman Smooth Start (MRS) lawn mower 591040 .030”

If you have a Quantum engine, be sure to check the Code Date before doing any engine maintenance.

Replacement Part Type Briggs & Stratton
Spark Plug Part Number
Spark Plug Gap
Resistor used on Vanguard models 050032 and 086400
only (Replaces Champion RC12YC)
Resistor (Replaces Champion RC12YC)
Electromagnetic Suppression (EMS)
(Replaces Champion QC12YC)
Extended Life Series® OHV Spark Plug Platinum 
(Replaces Champion RC12YC)
5066 (5066D, 5066H)
Resistor Spark plug - hotter spark 
(Replaces Champion RC14YC)
Electromagnetic Suppression (EMS)
(If not Chamion QC12YC model; 
check Illustrated Parts List to confirm)
692720 .030”

WARNING: Always read the engine and equipment manual(s) before starting, operating, or servicing your engine or equipment to avoid personal injury or property damage. See an authorized dealer or contact Briggs & Stratton if you are unsure of any procedure or have additional questions.